bool
vec4_visitor::opt_copy_propagation(bool do_constant_prop)
{
bool progress = false;
struct copy_entry entries[alloc.total_size];
memset(&entries, 0, sizeof(entries));
foreach_block_and_inst(block, vec4_instruction, inst, cfg) {
/* This pass only works on basic blocks. If there's flow
* control, throw out all our information and start from
* scratch.
*
* This should really be fixed by using a structure like in
* src/glsl/opt_copy_propagation.cpp to track available copies.
*/
if (!is_dominated_by_previous_instruction(inst)) {
memset(&entries, 0, sizeof(entries));
continue;
}
/* For each source arg, see if each component comes from a copy
* from the same type file (IMM, GRF, UNIFORM), and try
* optimizing out access to the copy result
*/
for (int i = 2; i >= 0; i--) {
/* Copied values end up in GRFs, and we don't track reladdr
* accesses.
*/
if (inst->src[i].file != GRF ||
inst->src[i].reladdr)
continue;
/* We only handle single-register copies. */
if (inst->regs_read(i) != 1)
continue;
int reg = (alloc.offsets[inst->src[i].reg] +
inst->src[i].reg_offset);
/* Find the regs that each swizzle component came from.
*/
struct copy_entry entry;
memset(&entry, 0, sizeof(copy_entry));
int c;
for (c = 0; c < 4; c++) {
int channel = BRW_GET_SWZ(inst->src[i].swizzle, c);
entry.value[c] = entries[reg].value[channel];
/* If there's no available copy for this channel, bail.
* We could be more aggressive here -- some channels might
* not get used based on the destination writemask.
*/
if (!entry.value[c])
break;
entry.saturatemask |=
(entries[reg].saturatemask & (1 << channel) ? 1 : 0) << c;
/* We'll only be able to copy propagate if the sources are
* all from the same file -- there's no ability to swizzle
* 0 or 1 constants in with source registers like in i915.
*/
if (c > 0 && entry.value[c - 1]->file != entry.value[c]->file)
break;
}
if (c != 4)
continue;
if (do_constant_prop && try_constant_propagate(devinfo, inst, i, &entry))
progress = true;
if (try_copy_propagate(devinfo, inst, i, &entry))
progress = true;
}
/* Track available source registers. */
if (inst->dst.file == GRF) {
const int reg =
alloc.offsets[inst->dst.reg] + inst->dst.reg_offset;
/* Update our destination's current channel values. For a direct copy,
* the value is the newly propagated source. Otherwise, we don't know
* the new value, so clear it.
*/
bool direct_copy = is_direct_copy(inst);
entries[reg].saturatemask &= ~inst->dst.writemask;
for (int i = 0; i < 4; i++) {
if (inst->dst.writemask & (1 << i)) {
entries[reg].value[i] = direct_copy ? &inst->src[0] : NULL;
entries[reg].saturatemask |=
inst->saturate && direct_copy ? 1 << i : 0;
}
}
/* Clear the records for any registers whose current value came from
* our destination's updated channels, as the two are no longer equal.
*/
if (inst->dst.reladdr)
memset(&entries, 0, sizeof(entries));
else {
for (unsigned i = 0; i < alloc.total_size; i++) {
for (int j = 0; j < 4; j++) {
if (is_channel_updated(inst, entries[i].value, j)) {
entries[i].value[j] = NULL;
entries[i].saturatemask &= ~(1 << j);
}
}
}
}
}
}
if (progress)
invalidate_live_intervals();
return progress;
}
bool
vec4_visitor::opt_copy_propagation(bool do_constant_prop)
{
/* If we are in dual instanced or single mode, then attributes are going
* to be interleaved, so one register contains two attribute slots.
*/
const int attributes_per_reg =
prog_data->dispatch_mode == DISPATCH_MODE_4X2_DUAL_OBJECT ? 1 : 2;
bool progress = false;
struct copy_entry entries[alloc.total_size];
memset(&entries, 0, sizeof(entries));
foreach_block_and_inst(block, vec4_instruction, inst, cfg) {
/* This pass only works on basic blocks. If there's flow
* control, throw out all our information and start from
* scratch.
*
* This should really be fixed by using a structure like in
* src/glsl/opt_copy_propagation.cpp to track available copies.
*/
if (!is_dominated_by_previous_instruction(inst)) {
memset(&entries, 0, sizeof(entries));
continue;
}
/* For each source arg, see if each component comes from a copy
* from the same type file (IMM, VGRF, UNIFORM), and try
* optimizing out access to the copy result
*/
for (int i = 2; i >= 0; i--) {
/* Copied values end up in GRFs, and we don't track reladdr
* accesses.
*/
if (inst->src[i].file != VGRF ||
inst->src[i].reladdr)
continue;
/* We only handle register-aligned single GRF copies. */
if (inst->size_read(i) != REG_SIZE ||
inst->src[i].offset % REG_SIZE)
continue;
const unsigned reg = (alloc.offsets[inst->src[i].nr] +
inst->src[i].offset / REG_SIZE);
const copy_entry &entry = entries[reg];
if (do_constant_prop && try_constant_propagate(devinfo, inst, i, &entry))
progress = true;
else if (try_copy_propagate(devinfo, inst, i, &entry, attributes_per_reg))
progress = true;
}
/* Track available source registers. */
if (inst->dst.file == VGRF) {
const int reg =
alloc.offsets[inst->dst.nr] + inst->dst.offset / REG_SIZE;
/* Update our destination's current channel values. For a direct copy,
* the value is the newly propagated source. Otherwise, we don't know
* the new value, so clear it.
*/
bool direct_copy = is_direct_copy(inst);
entries[reg].saturatemask &= ~inst->dst.writemask;
for (int i = 0; i < 4; i++) {
if (inst->dst.writemask & (1 << i)) {
entries[reg].value[i] = direct_copy ? &inst->src[0] : NULL;
entries[reg].saturatemask |=
inst->saturate && direct_copy ? 1 << i : 0;
}
}
/* Clear the records for any registers whose current value came from
* our destination's updated channels, as the two are no longer equal.
*/
if (inst->dst.reladdr)
memset(&entries, 0, sizeof(entries));
else {
for (unsigned i = 0; i < alloc.total_size; i++) {
for (int j = 0; j < 4; j++) {
if (is_channel_updated(inst, entries[i].value, j)) {
entries[i].value[j] = NULL;
entries[i].saturatemask &= ~(1 << j);
}
}
}
}
}
}
if (progress)
invalidate_live_intervals();
return progress;
}
